Premier League Preview

"It is difficult to imagine Manchester United having another season like last time out under Louis van Gaal. It's easy to laud a manager through past stories but contemporary examples back up the point that Van Gaal could be United's biggest strength."

Sporting president Bruno de Carvalho, though, has hit out at Rojo and team-mate Islam Slimani - who has been linked with West Ham and Leicester - for failing to be "professional" in their efforts to secure moves away and said the duo will not be selected for Saturday's Portuguese league opener against Academica.

"They will not play next weekend," De Carvalho said. "This will take as long as it takes. If something doesn't change, you're going to end up with the players seeing out their contracts.

"They can watch the game on television. On Saturday, against Academica, we will play to win and we will win. There is no player bigger than the club. I would not give up the honour, the club's history, for the attitudes of anyone.

"I give a piece of advice: don't use the press, be professional. These two, in defence of our magnificent group, must be removed. They are subject to strong disciplinary measures.

"Both players have taken decisions that have caused sharp indiscipline at Sporting. A message: any player who does not follow the rules of the club can have illusions and pretensions, but with the way these two did things, the situation is just complicated."

With Van Gaal looking to further boost his squad before the transfer window closes, Daley Blind - who starred for United's new manager with the Netherlands at the World Cup - has also been linked with a switch to Old Trafford.

"I am happy here in Amsterdam," the Ajax defender said. "But if there comes another club I will have to think about it and then we will see. I will think about my options. For now I will focus on Ajax and we will see what happens next week."

Angel di Maria may also be the subject of a £50m bid from United after the midfielder was an unused substitute for Real Madrid's Super Cup win against Sevilla on Tuesday, despite being named man-of-the-match for Real's Champions League final victory over Atletico Madrid in May.

Carlo Ancelotti gave new signing James Rodriguez his first start following his £63m move from Monaco, while £24m summer signing Toni Kroos was also included in what was the most expensive starting XI in history.

"Until now he is a Real Madrid player and we will have to wait to see what will happen," said Ancelotti after the victory in Cardiff.

Van Gaal appeared to hint at his interest in Di Maria after labelling him a winger of the "highest level" at the weekend.

United have already spent a combined £56m on Luke Shaw and Ander Herrera. Moves for Rojo, Di Maria and Blind could take United's summer outlay past the £150m mark, though executive vice-chairman Ed Woodward has set no limits on the transfer funds available to Van Gaal.